Did you know Smogon OU allows (or will allow) Pokémon as far back as Ruby and Sapphire? Anyone who plays VGC knows this, and as a judge, I MUST know this.
I don't have time to go to any VGC tournaments until sometime next year, so I can wait until Bank is released to make a team. Which is why I'm waiting for a 6IV Ditto first.
For singles, and pretty much everything that isn't VGC, I will be using whatever I feel like. If that means it's from XY or even RSE, then that's what it means. I have plenty of Pokémon on ORAS that I RNGed on Black, and I have every intention of transferring them up to Moon.